The present invention relates to the field of portable, dial tone multi-frequency (DTMF) telephone number dialer devices.
Dialing telephone numbers can be a daunting task. Most telephone numbers consist of seven digits. In the United States, if you need to dial an area code of four digits then the number increases to eleven. The situation is similar in other countries. International access and country codes add five or six more. If in addition, you have to use a calling card you must dial a whole other phone number, usually including an area code, wait for some key or instructions, then dial an access number before you even start to dial the desired phone number. It can be seen that around 22 to 27 digits need to be dialed to make a connection. If you make a mistake in dialing this long sequence of numbers, you must start over again. The whole process of making a phone connection is fraught with the possibility of error. If you are making a call from a telephone kiosk in a noisy airport, holding your calling card in one hand and your notebook in the other with the telephone receiver cradled under your neck, the possibility of making a mistake in dialing increases exponentially.
For many years now, DTMF signals have been used for dialing telephone numbers. Many people realized that the process of dialing the phone could be simplified by utilizing a device that could store the long sequences of tones necessary to dial the phone. Phone makers have produced phones with a limited number of memory registers that can be accessed with the push of a button.
Telephone calling cards have achieved popularity as a means to reduce the cost and bother of making long distance and international calls from pay and hotel phones. Using a calling card obviates the need to carry massive amounts of change for the pay phone. It also avoids the expense of connecting through a hotel switchboard. Many calling card companies offer discounted long distance rates also.
However, as pointed out above, using a calling card does not represent the ultimate in convenience because of the large number of digits that must be dialed to make a connection. There are a large number of patents covering electronic calling cards but they suffer from a number of deficiencies.
Development of a combination telephone calling card and dialer which can automatically, reliably and simply dial a preprogrammed phone number, then dial a preprogrammed access number and, optionally, a preprogrammed personal identification number (PIN) represents a great improvement in the field of telephone calling cards and satisfies a long felt need of people who frequently use public and hotel telephones.